HeatGear fabric is ultra-soft & smooth for extreme comfort with very little weight Mesh back & underarm panels deliver strategic ventilation 4-way stretch construction moves better in every direction Material wicks sweat & dries really fast Under Armour’s mission is to make all athletes better through passion, design and the relentless pursuit of innovation 90% Polyester, 10% Elastane Imported M = chest width 51cm, L = chest width 54cm, XL = chest width 57cm,